Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, pursuant to the Answer of 25 November 2025 to Question 87433 on Hereditary Diseases, for what reasons reporting of parental consanguinity within the National Disease Registration Service congenital conditions dataset remains incomplete; what assessment he has made of the impact of this incomplete reporting on the accuracy and usefulness of prevalence data; and what steps his Department is taking to help tackle this and improve compliance.

Since assuming responsibility for the registration of congenital and rare conditions in 2015, the National Disease Registration Service (NDRS) has focused on improving the accuracy of case completeness and strengthening regional coverage to monitor trends in congenital and rare conditions. NDRS is reviewing the data items recommended for reporting of congenital conditions, including which information should be collected through specialist congenital condition registration datasets and which is better captured for all pregnancies through the Maternity Services Data Set. NDRS has not assessed completeness of the consanguinity field at a provider level. NHS England is working to improve the recording of consanguinity. NDRS continues to work closely with reporting trusts, maternity services, and clinical teams to improve the quality and completeness of congenital condition data, supported by a dedicated data liaison function.